Plasmon Antenna Gap Positioning for Thermal Assistance
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Solution Overview
Problem
Conventional plasmon antennas for thermally assisted magnetic recording face challenges in near-field light generation efficiency and manufacturing cost, particularly when using TE-polarized laser beams, and their structure hinders effective application of the write magnetic field due to the gap position relative to the magnetic pole.
Innovation Solution
A plasmon antenna design with a pair of small metal bodies, preferably trapezoidal or parallelogram-shaped, positioned close to the magnetic pole, where the gap between them is optimized to enhance near-field light intensity and allow for efficient write magnetic field application, using metals like Au or Ag for resonance, and a manufacturing method involving flat lapping or milling to control the gap distance for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional bow-tie plasmon antenna structure is used, then near-field light is generated at the gap position, but the magnetic pole position is spaced apart from the gap position making it difficult to apply write magnetic field before medium cools down
Solution Approach 1:
The patent transitions from a conventional bow-tie antenna structure where the gap is positioned laterally to a structure where the gap is positioned in the depth direction (Z-axis) close to the magnetic pole. This dimensional repositioning allows the gap to be located at a distance of 0-50nm from the magnetic pole leading end, enabling effective thermal assistance while maintaining proper magnetic field application geometry
Solution Approach 2:
The plasmon antenna structure is designed with the gap nested within the optical waveguide core, positioned in the depth direction rather than lateral direction. This nested configuration allows the gap to be embedded close to the magnetic pole without interfering with the overall head structure, achieving both compact integration and effective thermal assistance
2Ease of manufacture
If TE-polarized laser beam is used for plasmon antenna excitation, then manufacturing cost and transmission loss are reduced, but conventional structures cannot efficiently generate near-field light with TE polarization
Solution Approach 1:
The patent changes the geometric parameters of the plasmon antenna structure, specifically positioning the gap in the depth direction (Z-axis) at 0-50nm from the magnetic pole leading end, rather than laterally as in conventional structures. This parameter change enables the antenna to efficiently couple with TE-polarized light and generate strong near-field light for thermal assistance
Solution Approach 2:
The redesigned plasmon antenna structure achieves multi-functionality by being able to efficiently operate with TE-polarized laser beams while maintaining effective near-field light generation. This universal design allows the same structure to achieve both cost-effectiveness (using standard TE-polarized sources) and high performance (sufficient thermal assistance for magnetic recording)
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design enables sufficient thermally assisted magnetic recording before the medium cools down, increasing recording density and simplifying manufacturing by enhancing near-field light intensity and allowing precise writing with a closer gap distance between the small metal bodies and the magnetic pole.
Implementation Method 1
The plasmon antennas used for such heating exhibit plasmon resonance, generating near-field light as a result, when irradiated by a laser beam
Implementation Method 2
a plasmon antenna comprising a pair of small metal bodies irradiated with excitation light for near-field light generation
Data Source
AI summary
A plasmon antenna of the present invention is used in a thermally assisted magnetic head that includes: a medium-facing surface set, parallel to an XY plane; a magnetic pole for writing, extending toward the medium-facing surface, and a plasmon antenna comprising a pair of small metal bodies irradiated with excitation light for near-field light generation propagating in a Z-axis direction. Respective corners of the small metal bodies are spaced apart opposite each other along a TE mode direction of the excitation light. A distance between the corners gives the shortest distance between the small metal bodies, and a distance from each corner to the leading end of the magnetic pole gives a shortest distance from the small metal bodies to the leading end.